Recently, various power supply units used to boost a low DC voltage are being developed for electronic devices based on a fuel cell or battery. In particular, a boost converter using a tapped inductor is launched in the market in order to satisfy a high boost ratio, high power conversion efficiency, and low manufacturing cost.
The boost converter using the tapped inductor is manufactured by adding the tapped inductor serving as a transformer to the boost converter. In connection with the boost converter using the tapped inductor, Korean Patent Publication No. 2010-0082084 A (laid-open published on Jul. 16, 2010) discloses a method of embodying a zero-voltage turn-on and zero-current turn-off function by using a tapped inductor of the boost converter.
In the boost converter using tapped inductor, it is possible to obtain a high boost ratio, but an inductor and a capacitor of a switch causes an occurrence of resonance when the switch is turned off. As a result, a surge voltage is generated across the switch, which incurs an excessive stress on the switch. Hence, the boost converter using tapped inductor needs to use a high withstand voltage diode and a dissipative snubber.